Evaporator for refrigerating apparatus



June 17, 1930. LBRUEHL 1,764,192

EVAPORATOR FOR REFRIGERATI NG APPARATUS Original Filed Jan. 4, 1927 anvemtoz W M 33%;; A lflmur Patented June 17, 1930 UNITED STATES PAT ENT OFFIC LAWRENCE BRUEHL, OF BROOKLYN, NEW YORK, .ASSIGNOR TO GAS REFRIGERATION CORPORATION, OF SCH-ANTON, PENNSYLVANIA, A CORPORATION OF DELAWARE EVAPORATOR FOR R1511?RIGERA'JIING APPARATUS Application filed January 4, 1927, Serial No. 158,846. RenewedMarch 7, 1929.

This invention is an improvement in evaporators for refrigerating apparatus, particu larly of the absorption type. In this type of refrigerating apparatus, the refrigerant gas is separated from the absorbent liquid by the action of heat and is thereafter cooled to effect the liquefaction thereof. During the heating period, it often happens that a small amount of the absorbent liquid is also evaporated and passes over to the condenser and thence to the evaporator. As this liquid is not volatile to any considerable extent at the low temperature existing in the evaporator during the absorbing period, it will remain in the evaporator. After a large number of alternate heating and absorbing periods, there may accumulate such a quantity of the absorbent liquid in the evaporator as will seriously interfere with the efficiency of the apparatus.

The object of the present invention is to effect the automatic return of liquid from the evaporator to the absorber during each cycle of operation and to thereby maintain at all times proper operating conditions.

The present invention is an improvement in the apparatus disclosed and broadly claimed in the Otto and Jankus Patent 1,582,882 issued April 27, 1926. In the'construct ion illustrated in said patent there is provided a sump having the upper part in restricted communication with the bottom of the main chamber of the evaporator. In addition to the sump there is a pressure chamber connected thereto by a conduit.

As one important feature of my invention,- I provide a single chamber which serves both as a sump or receiver for the liquid drained from the body of the evaporator and as a pressure chamber in which the gas expands to force the liquid to a higher level.

As one simple way of carrying out my invention, I may extend a tube downwardly from the bottom of the main body of the evaporator to a point below the top of the sump and use this tube for the drainage of the liquid into the sump. Thus the space in the sump above the lower end of this conduit serves as a pressure chamber in which gas may accumulate and the expansion of such gas forces liquid out of the sump; By means of of heat absorption by the liquid to be returned.

In the construction shown in Fig. 1, there is provided an evaporator which may be of any suitable size, form or construction depending upon the characterof the apparatus in connection with which it is to be used and which is to be cooled thereby. I have shown this evaporator as a simple cylindrical drum, but such form. is not in any way essential. A conduit 11 communicates with the upper part of the evaporator and serves for the delivery of the liquefied refrigerant to the evaporator during the heating period and for the return of gas from the evaporator during the absorbing or cooling period.

At the lowermost portion of the evaporator. there is provided a sump 12 which may be of any suitable character, but is illustrated as of substantially the type shown in patent 1,582,-

882 above referred to. The lower portion of the evaporator has a very small ort 13 whereby liquid may drain from the body-of the evaporator into the sump.

As one important feature of my invention, I provide a tube 14 which leads downwardiy from this port 13 so that there a chamber arLpund the tube, which is closed at the top and s1 es.

A conduit 15 extends from the lower portion of the sump to the upper part. of the evaporator-s0 that liquid from the sump may be conveyed to a point from which it may be returned to the conduit 11. As shown there is a chamber 16 at the upper part of the evaporator and communicating with the body "I the evaporatorthrough a conduit 17. The conduit 11 extends into the chamber to'a point below the upper end of the conduit 17. The conduit 15 projects up into the chamber to a point above the upper end or the conduit 1'? and also above the lower end of the conduit 11. The upper end of the conduit 15 may have a cup or enlargement 18 to separate liquid and gas, and provided with ports for the escape of gas. l-Vhen considerable quantity of liquid or continuous stream of liquid is delivered up through. the conduit 15 it may overflow into the chamber 16, but when there is mere serging in conduit ll), gas and liquid wil eparate in cup 18 the liquid will be re Lirned rather tb taken from the evapothrough the co ll.

the operation my improved device any of the absorbent water or other absorbent liquid which has been delivered to the evaporator during the heating period will remain the bottom of the evaporator at the end of the cooling period. This liquid will drain through the port 13 to the sump. During the first part of the next succeeding heating period, the liquid will remain in the sump and may rise to a level higher than that or" the lower end of the tube 14 until it reaches the top of the sump 12 due to the compression and condensation of the gas in the upper part of the sump so that the sump filled with liquid during the latter part of the boiling period.

At the beginning or" the next coling period, the pressure in the system is. very materially reduced and shortly after the liquid in the upper part of the sump or chamber12 gasifies. This gas will collect in the chamber above the end of the tube 14-. The liquid in the lower part of the chamber may escape either through the tube 1% or the conduit 15, or both, but by reason of the fact that the passage through the conduit 15 is comparatively tree and unrestricted whereas the port 13 is of very small size, most of the liquid will be delivered through the conduit 15 to the chamber 16. As it accumulates in the latter, it will rise to a point above the lower end of the conduit ll. and will be sucked from the evaporator back to the absorber through this conduit 1.

Elf the sump or chamber 12 be so positioned that the upper part is above the bottom of the vessel the port 13 may be so positioned that the tube 14 is not necessary. The part of the chamber above the point of delivery or liquid constitutes the gas pressure part.

It will be noted that as the upper end of the conduit 15 is higher than the upper end of the conduit 1? all or the liquid delivered to the evaporator during the heating period will .tlow through the conduit 1'? to the body or" the evaporator instead of through the conduit 15 to the chamber 12. It will, of course, be evident that only a small amount of liquid will be returned from the sump during each cycle of operation, but this return of successive small quantities insures the maintenance of the system in the proper working condiaaeaioe 3 to consideral may be delivereo sump and whichmay more liquefied refrigerant.

Liquid will be delive" l 12 through the condun d e not only drop in pressure in the ratorx b to the absorption of he chamber, and th result' vapori such liquid. The rate of delivery from the chamber 12 to the conduit 15 may be controlled by regulating the rate of heat absorption by such liquid. in Fig. 4 l have shown a construction substantially the same as that shown in Fig. 1, except that there is pr0 vided a coil 20 which has one end connected to the upper part of the chamber 12 and the other end to the lower part. The liquid in the chamber may circulate through this coil and thus more rapidly absorb heat and more rapidly increase the pressure in the chamber at the beginning of the cooling period. In

I have shown another construction substantially the same as in Fig. 1, except that an insulating jacket 21 is formed around the chamber 12, so as to retard the absorption of heat. @no or the other of said constructions will be used depending on whether toe evaporator be used in brine or in Fi 2 I have shown another form of evaporator construction. This evaporator has a body portion and a combined liquid receiving and pressure chamber 12*, but the latter is not directly connected to the former. A conduit 22 extends from the upper part of the body 10 to the lower part of the chamber 12 it is open at the top and has a small port l3 adjacent to its lower end. A conduit extends through the conduit 22 and opens into the chamber 12 at the bottom of the latter and below a baflle 19 which may also serve as a closure for the lower end of the conduit 22. A coil 23 has an inlet end 24 connected to the bottom of the body of'the evaporator'and an outlet end connected to the conduit 12 preferably at a point spaced just above the chamber 12. The intermediate portion of the conduit 23 may be disposed in a plurality of approximately horizontal planes to form shelves or partition -for separate provision or ice making compartments 26.

In the operation of this form, the liquid refrigerant will enter the upper end of the coil 23, will absorb heatand become vaporized during the cooling period. The vapor yvill pass out into the upper part of the body 10 above the liquid level in the latter. Unevaporated liquid will collect in the lower end of the conduit 22 below the outlet 25 from the coil and will slowly flow through the port 13 to the chamber 12 During the next succes sive coding period, the liquid which has accumulated in the chamber 12 will be forced up the conduit 15 and returned to the absorber.

In the construction shown in Fig. 3 there is provided an evaporator having a body portion 10 but the chambers 16 and 12 are separate therefrom. The chamber 16* is connected to the upper part of the evaporator by a conduit 17*, while the chamber 12". is connected to the bottom of the evaporator by a conduit 1 1* which terminates in the chamber 12 at a point spaced to a considerable distance below the top of the chamber. The operation is substantially the same as in the construction shown in Fig. 1. The coil in the conduit 14* will serve to cause the rapid absorption of heat during the cooling period and the creation of a sufficient gas pressure inthe chamber 12 to force liquid up the conduit 15. The relative size of the chambers 12 and 10 mav be varied to cause any desired amount of liquid to be returned during each cycle of operations dependent upon the amount of absorbent liquid which comes over from the absorber.

In a construction of this kind it is not necessary to have the communication from the compartment 12 to the bottom of the receiver 10* restricted relatively to communication 15 for the following reason: Conduit 1 1' can even be larger than 15 On account of the fact that the coil takes in more heat from the outside than compartment 12, gas will be developed sooner in the coil than in compartment 12 so that in every'turn of the coil a liquid column is generated by which the pressure in compartment 12 is increased and so a resisttime is created to hinder the entrance of liquid from 12 to the coil when the gas in 12 is produced. After compartment 12 is in operation all liquid columns swing to the other side of each turn of the coil so that during the absorption period no further liquid enters compartment 12 and a continuous operation of compartment 12" is avoided.

Having thus described my invention, what I claim is:

1. An evaporator for absorption refrigeration systems including a main evaporator vessel, a chamber disposed therebeneath,

point below the top of the latter, and a liquid return conduit" leading from the lower portion of said chamber, the upper part of said chamber serving asa gas chamber to force liqutidfrom said chamber through said con- 2. An evaporator for absorption refrigeration systems including a main evaporator vessel, a chamber disposed therebeneath, a liquid passage. connecting the lower portion of the vessel with said chamber at a point below the top of the latter, and a liquid conduit leading from the lower portion of said chamber, the-cross sectional area of said conduit being very much larger than said passage.

3. An evaporator for intermittently operating refrigerating apparatus of the absorption type, having a main vaporization chamher, a compartment therebeneath, a restricted passage from the lowerportion of the vessel to the lower portion of the compartment, a conduit connected to the upper part of the vessel for the delivery of li uid theretoand the withdrawal of gas theretrom, and means for delivering liquid from the lower part of said compartment to said conduit 4:. An evaporator for refrigerating apparatus including a main vessel, a chamber therebeneath, a partition therein, a conduit leading from the bottom of the vessel to said chamber on one side of said partition and a liquid return conduit leading from said chamber at the other side of said partition.

5. An evaporator for refrigerating apparatus having a chamber at the lower part thereof, a restricted communication for the delivery of liquid to .the chamber at a point ratus including a vessel, a combined liquidw collecting and gas pressure chamber, a con- 1 duit for the delivery of liquid from the lower portion of the vessel to the lower portion of the chamber, and a conduit leading from the lower portion of said chamber to the upper portion of said evaporator for the delivery of liquid from said chamber, said first mentioned conduit being in the form of a coil.

7. An evaporator for absorption refriger ation systems including a main evaporator vessel a chamber disposed therebeneath, a conduit connecting the lower portion of the vessel with the lower portion of the chamber, and a liquid return conduit leading from the lower portion of said compartment, said first mentioned conduit being restricted and the second mentioned conduit being comparatively open.

8;. An evaporator for refrigerating apparatus including a vessel, a combined liquid collecting and gas pressure chamber, a conduit for the delivery of? liquid from the lower portion of the vessel to said chamber, the part of said chamber above the point oi delivery constituting the gas portion of said chamber, and means for delivering liquid from said chamber by the action of gas therein, upon drop in pressure in said evaporator.

9. on, orator for refrigerating apparatus inciud I a vessel, a combined liquid collecting I; i as pressure chamber, a hori zontal bat ie in said chamber, means tor delivering liquid from said vessel to said cham-v ber above said bathe, and means for Withdrawing liquid from said chamber permit ting restricted communication between the upper and l parts thereoi below said bab le.

10. An evap rator for re paratus oi? the intermittently acting absorption type, including" a refrigerant receiving vessel, a chamber therebeneath, a conduit having its upper end opening into the upper part of said vessel, and its-lower end having restricted communication with said chamber at a point below the top oi the latter, a heat absorbing conduit having its upper end openinginto the lower part or said vessel and its lower end communicating with said first mentioned conduit below said vessel and above said chamber, and a third conduit extending from the lower part of said chamber through said first mentioned conduit to the upper part or said essel above the upper end of said first mentioned conduit for delivering from said chamber the liquid entering the latte. one said second mentioned conduit, and unevaporated in its passage through the letter.

11. An evaporator for refrigerating apparatus of the intermittently acting absorp tion type, including a refrigerant liqlud re ceiving vessel, a chamber therebeneath, a heat aosorbing conduit havin its upper end opening into the lower part of said vessel, and its end communicating vvith the manor part said vessel, and in restricted cdiiimuhication with said chamber below the top thereof, ereby the unevaporated por tion of l" entering said conduit may collect in s chamber, and a conduit leading from ti e lower ortion of said chamber for delive- 4 liquid therefrom by the action of the gas in the upper portion of said chamber upon a drop in the pressure in the evaporat-or.

12. An evaporator'zior refrigerating apnaratus oithe intermittently acting absorption type, including refrigerant liquid receiving vessel, a chamber therebeneath, a heat absorbing conduit having its upper end opening into the lowerpart of said vessel, and its lower end in restricted communication with the lower portion of said chamber at a point below the top of the latter whereby the upper portion of said chamber terms a rigerating ap- ,ies

gas space, and a conduit leading from the lower portion of said chamber, the cross-sectional area of said conduit being greater than said restricted communication, whereby liquid'is delivered from said chamber upon a drop in pressure in the evaporator.

13. An evaporator for refrigerating apparatus of the intermittently operating type, including a vessel, a combined liquid collecting and gas pressure chamber, a heat absorbing conduit connecting" the lower portion of said vessel to the lower portion of said chamher, the communication with the chamber being restricted, and the lower end or said conduit having separate communication with the upper part of said vessel, and a conduit leading from the lower portion or said chamber for the delivery therefrom of liquidcollecting therein and unevaporated in its passage from said vessel through said first mentioned conduit.

14. An evaporator for refrigerating apparatus of the intermittently acting type, in cluding a vessel, a combined liquid collecting and gas pressure chamber therebeneath, a conduit having open communication with the upper part of said vessel and restricted communication with the lower part said chamber, a heat absorbing coil having its upper end connected to the bottom of said vessel and its lower end connected to said first mentioned conduit intermediate of the ends of the latter, and a liquid delivery conduit leading from the lower portion of said chamber.

15. An evaporator for refrigerating apparatus, including a vessel, a heat absorbing conduit having its upper end connected to the lovver part of said vessel, a liquid collecting chamber connected to the lower end of said conduit, the upper portion of said chamber being imperforate to form a gas space, and means for delivering liquid from the lower portion of said chamber upon drop in pressure oi the evaporator.

Signed at Brooklyn, in the county of Kings and tate of New York, this 31st day of December 1%.. 19., 1926.

LAWREN E 

